The present invention relates generally to scanning electron microscopes and, more particularly, to a scanning electronic microscope processor for analyzing semiconductor devices and a method of manufacturing an integrated circuit.
A large amount of activity in the microelectronics industry is directed toward developing methodologies for testing wafers during the manufacturing process. Typically, scanning electron microscopes (SEM) have been used in semiconductor manufacturing processes. Although the SEM is useful for providing some information regarding a semiconductor device that is scanned, it can be difficult for an operator to detect errors by simply viewing the waveform from the SEM. Usually, an operator operates a SEM in an automatic mode to measure critical line width. The measurement is derived from the intensity waveform produced by the SEM. The SEM is not utilized to extract processing variables from the topography of the wafer. The shape of the measured object is typically not considered.
In addition, cross-sections of wafers are performed to assess the quality of a wafer. Although this process may be useful, the process is destructive and time consuming. As a result, a small number of wafers are selected for testing. An alternative approach is to perform electrical tests at the end of wafer processing to determine if deficiencies exist and assess the quality of the semiconductor devices formed on the wafer. Although deficiencies may be found, the defects are not detected until the end of wafer processing. As a result, problems in the manufacturing process or with the equipment used during manufacturing may not be detected. Numerous defective wafers may be produced before problems with the manufacturing or measurement process can be corrected.
The present invention provides a method and system for analyzing the intensity profiles of a wafer including the step of scanning the wafer to produce a scanned signal. The scanned signal is preprocessed and compared to a reference signal to assess the wafer. The present invention is also directed to a method of manufacturing a wafer using the above method and system.
It is to be understood that both the foregoing general description and the following detailed description are exemplary, but are not restrictive, of the invention.